/Engine/Source/Runtime/GeometryCore/Public/Util/IndexUtil.h
Assuming [Vertex1,Vertex2] is an unordered edge in TriangleVerts, return Vertex1 and Vertex2 in the correct order (ie the same as TriangleVerts), and returns the vertex ID of the other vertex
ID of third vertex, or InvalidID if the edge was not found
namespace IndexUtil { template<typename T, typename Vec> int IndexUtil::OrientTriEdgeAndFindOtherVtx ( T & Vertex1, T & Vertex2, const Vec & TriangleVerts ) }